#include <stdio.h>
#include <time.h>
#include <string.h>

#include <stdint.h>
#include "md5.h"

//typedef unsigned char *POINTER; /* POINTER defines a generic pointer type */
//typedef unsigned short int UINT2; /* UINT2 defines a two byte word */
//typedef unsigned long int UINT4; /* UINT4 defines a four byte word */
//typedef struct {
//        UINT4 state[4];    /* state (ABCD) */
//        UINT4 count[2];        /* number of bits, modulo 2^64 (lsb first) */
//        unsigned char buffer[64]; /* input buffer */
//} MD5_CTX;

#define MAX_BUF_LEN     (1024 * 64)
#define MD 5

/* Length of test block, number of test blocks. */
#define TEST_BLOCK_LEN 1000
#define TEST_BLOCK_COUNT 1000

/* Constants for MD5Transform routine. */
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

char* MDString(char *);
char* MDFile(char *, char *);

char* hmac_md5(char* text, char* key);

static unsigned char PADDING[64] = {
0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

/* F, G, H and I are basic MD5 functions. */
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits. */
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation. */
#define FF(a, b, c, d, x, s, ac) { \
(a) += F ((b), (c), (d)) + (x) + (UINT4)(ac); \
(a) = ROTATE_LEFT ((a), (s)); \
(a) += (b); \
}
#define GG(a, b, c, d, x, s, ac) { \
(a) += G ((b), (c), (d)) + (x) + (UINT4)(ac); \
(a) = ROTATE_LEFT ((a), (s)); \
(a) += (b); \
}
#define HH(a, b, c, d, x, s, ac) { \
(a) += H ((b), (c), (d)) + (x) + (UINT4)(ac); \
(a) = ROTATE_LEFT ((a), (s)); \
(a) += (b); \
}
#define II(a, b, c, d, x, s, ac) { \
(a) += I ((b), (c), (d)) + (x) + (UINT4)(ac); \
(a) = ROTATE_LEFT ((a), (s)); \
(a) += (b); \
}

//void MD5Init (MD5_CTX *context);
//void MD5Update(MD5_CTX *context, unsigned char *input,unsigned int inputLen);

//void MD5Final (unsigned char digest[16], MD5_CTX *context);
static void MD5Transform (UINT4 [4], unsigned char [64]) ;
static void Encode(unsigned char *, UINT4 *, unsigned int);
static void Decode (UINT4 *, unsigned char *, unsigned int);
static void MD5_memcpy(POINTER, POINTER, unsigned int);
static void MD5_memset(POINTER, int, unsigned int);

/* MD5 initialization. Begins an MD5 operation, writing a new context. */
void MD5Init (MD5_CTX *context) /* context */
{
context->count[0] = context->count[1] = 0;
/* Load magic initialization constants. */
context->state[0] = 0x67452301;
context->state[1] = 0xefcdab89;
context->state[2] = 0x98badcfe;
context->state[3] = 0x10325476;
}

/* MD5 block update operation. Continues an MD5 message-digest
operation, processing another message block, and updating the context. */
void MD5Update (MD5_CTX *context, unsigned char *input, unsigned int inputLen)
     /* context */ /* input block */ /* length of input block */
{
unsigned int i, index, partLen;

/* Compute number of bytes mod 64 */
index = (unsigned int)((context->count[0] >> 3) & 0x3F);

/* Update number of bits */
if ((context->count[0] += ((UINT4)inputLen << 3)) < ((UINT4)inputLen << 3))
   context->count[1]++;
context->count[1] += ((UINT4)inputLen >> 29);

partLen = 64 - index;

/* Transform as many times as possible. */
if (inputLen >= partLen)
{
    MD5_memcpy ((POINTER)&context->buffer[index], (POINTER)input, partLen);
    MD5Transform (context->state, context->buffer);

   for (i = partLen; i + 63 < inputLen; i += 64)
       MD5Transform (context->state, &input[i]);
    index = 0;
}
else
    i = 0;

/* Buffer remaining input */
MD5_memcpy ((POINTER)&context->buffer[index], (POINTER)&input[i], inputLen-i);
}

/* MD5 finalization. Ends an MD5 message-digest operation, writing the
the message digest and zeroizing the context. */
void MD5Final (unsigned char digest[16], MD5_CTX *context)
     /* message digest */ /* context */
{
unsigned char bits[8];
unsigned int index, padLen;

/* Save number of bits */
Encode (bits, context->count, 8);

/* Pad out to 56 mod 64.*/
index = (unsigned int)((context->count[0] >> 3) & 0x3f);
padLen = (index < 56) ? (56 - index) : (120 - index);
MD5Update (context,(unsigned char*) PADDING, padLen);

/* Append length (before padding) */
MD5Update (context, bits, 8);
/* Store state in digest */
Encode (digest, context->state, 16);

/* Zeroize sensitive information.*/
MD5_memset ((POINTER)context, 0, sizeof (*context));
}

/* MD5 basic transformation. Transforms state based on block. */
static void MD5Transform (UINT4 state[4], unsigned char block[64])
{
int i=0;
(void)i;
UINT4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
Decode (x, block, 64);

/* Round 1 */
FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

/* Round 2 */
GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
GG (d, a, b, c, x[10], S22, 0x2441453); /* 22 */
GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

/* Round 3 */
HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
HH (b, c, d, a, x[ 6], S34, 0x4881d05); /* 44 */
HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

/* Round 4 */
II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

state[0] += a;
state[1] += b;
state[2] += c;
state[3] += d;

/* Zeroize sensitive information. */
MD5_memset ((POINTER)x, 0, sizeof (x));
}

/* Encodes input (UINT4) into output (unsigned char). Assumes len is
a multiple of 4. */
static void Encode (unsigned char *output,UINT4 *input,unsigned int len)
{
unsigned int i, j;

for (i = 0, j = 0; j < len; i++, j += 4)
{
   output[j] = (unsigned char)(input[i] & 0xff);
   output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
   output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
   output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
}
}

/* Decodes input (unsigned char) into output (UINT4). Assumes len is a multiple of 4. */
static void Decode (UINT4 *output,unsigned char *input,unsigned int len)
{
unsigned int i, j;

   for (i = 0, j = 0; j < len; i++, j += 4)
    output[i] = ((UINT4)input[j]) | (((UINT4)input[j+1]) << 8) |
      (((UINT4)input[j+2]) << 16) | (((UINT4)input[j+3]) << 24);
}

/* Note: Replace "for loop" with standard memcpy if possible. */
static void MD5_memcpy (POINTER output,POINTER input,unsigned int len)
{
unsigned int i;

for (i = 0; i < len; i++)
   output[i] = input[i];
}

/* Note: Replace "for loop" with standard memset if possible. */
static void MD5_memset (POINTER output,int value,unsigned int len)
{
unsigned int i;

for (i = 0; i < len; i++)
    ((char *)output)[i] = (char)value;
}

/* Digests a string and prints the result. */
char* MDString (char *string)
{
MD5_CTX context;
unsigned char digest[16];
char output1[32];
static char output[33]={""};
unsigned int len = strlen (string);
int i;
MD5Init (&context);
MD5Update (&context, (unsigned char*)string, len);
MD5Final (digest, &context);

for (i = 0; i < 16; i++)
{
   sprintf(&(output1[2*i]),"%02x",(unsigned char)digest[i]);
   sprintf(&(output1[2*i+1]),"%02x",(unsigned char)(digest[i]<<4));
}
for(i=0;i<32;i++)
   output[i]=output1[i];
return output;
}

/* Digests a file and prints the result. */
char* MDFile(char *filename, char *output)
{
#if 0
static char output[33]={""};
#endif

FILE *file;
MD5_CTX context;
int i, len;

unsigned char buffer[MAX_BUF_LEN], digest[16];
char output1[32];
if ((file = fopen (filename, "rb")) == NULL)
   {
   printf ("%s can't be openedn", filename);
   return 0;
   }
else
{
    MD5Init (&context);
#if 0
    while (len = (int)fread ((void*)buffer, 1, MAX_BUF_LEN, file))
          MD5Update (&context, buffer, len);
#endif
    do {
	    len = fread((void*)buffer, 1, MAX_BUF_LEN, file);
	    if (!len){
		    break;
	    }
            MD5Update (&context, buffer, len);
    }while(len);
    MD5Final (digest, &context);
    fclose (file);
    for (i = 0; i < 16; i++)
     {
       sprintf(&(output1[2*i]),"%02x",(unsigned char)digest[i]);
        sprintf(&(output1[2*i+1]),"%02x",(unsigned char)(digest[i]<<4));
        }
        for(i=0;i<32;i++)
          output[i]=output1[i];
        return output;
    }
}

char* MDFile1(char *filename, char *output, uint64_t offset)
{
#if 0
static char output[33]={""};
#endif

FILE *file;
MD5_CTX context;
int i, len;

unsigned char buffer[MAX_BUF_LEN], digest[16];
char output1[32];
if ((file = fopen (filename, "rb")) == NULL)
   {
   printf ("%s can't be openedn", filename);
   return 0;
   }
else
{
    fseek(file, offset, SEEK_SET);

    MD5Init (&context);
#if 0
    while (len = (int)fread ((void*)buffer, 1, MAX_BUF_LEN, file))
          MD5Update (&context, buffer, len);
#endif
    do {
	    len = fread((void*)buffer, 1, MAX_BUF_LEN, file);
	    if (!len){
		    break;
	    }
            MD5Update (&context, buffer, len);
    }while(len);
    MD5Final (digest, &context);
    fclose (file);
    for (i = 0; i < 16; i++)
     {
       sprintf(&(output1[2*i]),"%02x",(unsigned char)digest[i]);
        sprintf(&(output1[2*i+1]),"%02x",(unsigned char)(digest[i]<<4));
        }
        for(i=0;i<32;i++)
          output[i]=output1[i];
        return output;
    }
}

char* hmac_md5(char* text,char* key)
{
    char digest[16];
    char output1[32];
    static char output[33]={""};
    MD5_CTX context;
    unsigned char k_ipad[65]; /* inner padding -key XORd with ipad */
    unsigned char k_opad[65]; /* outer padding -key XORd with opad */
    unsigned char tk[16];
    int i;
    int text_len = strlen (text);
    int key_len=strlen(key);
    /* if key is longer than 64 bytes reset it to key=MD5(key) */
    if (key_len > 64)
    {
       MD5_CTX tctx;
       MD5Init(&tctx);
       MD5Update(&tctx,(unsigned char*) key, key_len);
       MD5Final(tk, &tctx);
       key = (char*)tk;
    key_len = 16;
    }

    /*
     * the HMAC_MD5 transform looks like:
     *
     * MD5(K XOR opad, MD5(K XOR ipad, text))
     *
     * where K is an n byte key
     * ipad is the byte 0x36 repeated 64 times
     * opad is the byte 0x5c repeated 64 times
     * and text is the data being protected
     */

    /* start out by storing key in pads */
   
    /* bzero( k_ipad, sizeof k_ipad);
       bzero( k_opad, sizeof k_opad);
    */

    for(i=0;i<65;i++)
    k_ipad[i]=(unsigned char)0;
    for(i=0;i<65;i++)
    k_opad[i]=(unsigned char)0;

    /* bcopy( key, k_ipad, key_len);
       bcopy( key, k_opad, key_len);
     */
    for(i=0;i<key_len;i++)
    {
    k_ipad[i]=(unsigned char)key[i];
     k_opad[i]=(unsigned char)key[i];
    }

    /* XOR key with ipad and opad values */
    for (i=0; i<64; i++)
    {
        k_ipad[i] ^= 0x36;
        k_opad[i] ^= 0x5c;
    }
    /* perform inner MD5 */
    MD5Init(&context); /* init context for 1st pass */
    MD5Update(&context, k_ipad, 64); /* start with inner pad */
    MD5Update(&context, (unsigned char*)text, text_len); /* then text of datagram */
    MD5Final((unsigned char*)digest, &context);          /* finish up 1st pass */
    /* perform outer MD5 */
    MD5Init(&context); /* init context for 2nd * pass */
    MD5Update(&context, k_opad, 64); /* start with outer pad */
    MD5Update(&context,(unsigned char*) digest, 16);     /* then results of 1st hash */
    MD5Final((unsigned char*)digest, &context);          /* finish up 2nd pass */
    for (i = 0; i < 16; i++)
    {
    sprintf(&(output1[2*i]),"%02x",(unsigned char)digest[i]);
     sprintf(&(output1[2*i+1]),"%02x",(unsigned char)(digest[i]<<4));
    }
    for(i=0;i<32;i++)
    output[i]=output1[i];
    return output;    
}
